1. Field of the Invention
The present invention relates to a filtration material for desalination, and in particular relates to a filtration material made of a water-swellable polymer.
2. Description of the Related Art
Currently, filtration materials for desalination which are applied to sea water, industrial water and wastewater, have been developed by various sources all around the world. Conventionally, design issues concern the efficient treatment of salt water, the reduction of operating pressure, low energy consumption, and reduction in the cost of water treatment.
U.S. Pat. No. 4,828,700 discloses a membrane made of cross-linked poly methyl methacrylate. The membrane performance has a 9.1 GFD flux, and a 97.9% salt rejection, when tested under an operation pressure of 400 psi using 2500 ppm of salt water.
U.S. Pat. No. 5,755,964 discloses a reverse osmosis (RO) membrane, wherein the RO membrane has good wetting property by using an amine compound to treat the surface of the RO membrane. The RO membrane performance has a 48 GFD flux, when tested under an operation pressure of 225 psi using 2000 ppm of salt water. The RO membrane exhibits high flux like nanofiltration material.
The filtration materials for desalination in prior art are made of nanoporous polymeric thin film. However, the nanoporous polymeric thin film must be operated under a high pressure. Alternatively, if the filtration materials are made of hydrophilic materials, the operation pressure may be decreased, which would thereby improve desalination efficiency.